using System;

using OpenTK.Graphics.OpenGL;
using OpenTK.Graphics;
using OpenTK;

namespace org.nhengine.graphics
{
	public class GLCamera
	{
		Vector3 vPosition;			// Position der Kamera
		Vector3 vDirection;			// Blickrichtung der Kamera

		float fDistance;            // Zusätzliche Distanz der Kamera entgegen der Blickrichtung

		Matrix4 mTranslation;		// Matrix für Translation
		Matrix4 mRotation;          // Matrix für Rotation
		Matrix4 mDistance;			// Matrix für Rückzug entgegen der Blickrichtung
		Matrix4 mProjection;        // Projektionsmatrix

		public GLCamera()
		{
			vPosition = new Vector3(0,0,0);
			vDirection = Vector3.UnitZ;
			fDistance = 0.0f;

			mProjection = Matrix4.CreatePerspectiveFieldOfView(
				MathHelper.PiOver4,
				1.0f,
				0.1f,
				100000.0f
				);

			mRotation = Matrix4.Identity;

			glPrepare();
		}

		public void setViewport(int width, int height)
		{
			mProjection = Matrix4.CreatePerspectiveFieldOfView(
				MathHelper.PiOver4,
				width / (float)height,
				1.0f,
				1000000.0f
				);
		}

		private void glPrepare(){
			this.mTranslation	= Matrix4.CreateTranslation(vPosition * -1.0f);
			this.mDistance		= mRotation * Matrix4.CreateTranslation(0, 0, -fDistance);

		//	Console.WriteLine("View Direction:  {0}", vDirection);
		//	Console.WriteLine("Rotation Matrix: {0}", mRotation);

		}

		private void glUpdate(){
			
		}

		public void use(ShaderProgram sp){
			glUpdate();

		}


		public Matrix4 MTranslation
		{
			get
			{
				return mTranslation;
			}
		}

		public Matrix4 MRotation
		{
			get
			{
				return mRotation;
			}
			set {
				this.mRotation = value;
			}
		}

		public Matrix4 MDistance
		{
			get
			{
				return mDistance;
			}
		}

		public Matrix4 MProjection
		{
			get
			{
				return mProjection;
			}
		}

		public float Distance
		{
			get
			{
				return fDistance;
			}

			set
			{
				fDistance = value;
				glPrepare();
			}
		}
/*
		public Vector3 Direction {
			get { return this.vDirection; }
			set { this.vDirection = value; glPrepare(); }
		}
*/
		public Vector3 Position {
			get { return this.vPosition; }
			set { this.vPosition = value; glPrepare(); }
		}


	}
}